Stockholders' Equity (Schedule of Restricted Stock Grants) (Details) - Restricted Stock - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award
Granted (in shares)	0	14,018	17,439
Weighted average stock price (in usd per share)	$ 0	$ 92.25	$ 74.55
Fair value of stock granted	$ 0	$ 1,293	$ 1,300

Stock Issued During Period, Value Per Share, Restricted Stock Award

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Number of shares issued during the period related to Restricted Stock Awards, net of any shares forfeited.

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Value of stock related to Restricted Stock Awards issued during the period, net of the stock value of such awards forfeited.

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